The present invention is directed to a gas discharge display tube, which has a rear wall and has a plurality of cathode strips, which are disposed to extend parallel to one another, are isolated from one another and are separately actuated.
A gas discharge display device, which has a cathode formed by a plurality of parallel strips, which were isolated from each other, and were separately actuated, is disclosed in German Offenlegungsschrift No. 26 43 915, which was the basis for U.S. Pat. No. 4,130,778. The division of the cathode into several strip-shaped cathodes, which are insulated from one another, was a further development of a surface cathode, such as was required for gas discharge display tubes, which is known and, for example, described in German Offenlegungsschrift No. 24 12 869, which was the basis for U.S. Pat. No. 3,956,667, and which disclosed a so-called plasma panel, or plasma or gas discharge display.
The above display functions according to the principle of a spatial separation of electron generation and the electron acceleration. The tube utilized to this end is divided into two chambers, which are interconnected by a conductor matrix provided with holes at the intersecting points of rows and colums of electrodes. The rear chamber, as viewed from the observer's point of view, is the space for the gas discharge which is sealed off by the surface cathode at the rear wall of the tube and by the strip-shaped auxiliary anodes arranged in rows on the conductor matrix. The front chamber is the post acceleration space between the column plane of the column electrodes of the conductor matrix and the surface anode which represents a fluorescent screen electrode. By actuating or operating one of the auxiliary anodes, a wedge-shaped gas discharge results between the surface cathode and the axuiliary anode over the entire length of the two. In the event of simultaneous actuation of one of the strip-shaped control electrodes serving as a matrix column, the plasma electrons generated in the gas discharge are drawn through the opening at the intersection point of the row and the column into the post acceleration space and to the anode. At the impact location, there will then result on the illuminescent material disposed in front of the anode, a light point as an image of the activated intersection point of the matrix. With corresponding matrix actuations in accordance with a chronological sequence and strength, characters and images can be represented on the fluorescent screen.
In order to guarantee the wedge-shaped gas discharge in every operating condition, the surface cathode is advantageously divided into a plurality of partial cathodes or strip cathodes which extend parallel to the auxiliary anodes. A group of the auxiliary anodes is then associated with each partial or strip cathode. Through an actuation of a partial or strip cathode, which is concommitant with the auxiliary anode actuation, the wedge-shaped gas discharge results only between specific auxiliary anodes and specific partial or strip cathodes. The division of the cathode, i.e. the number of cathode strips and the number of auxiliary anodes of a group which are allotted to each cathode strip, is dependent upon the application purposes and the operating parameters such as the type of gas and gas pressure being used.